WATER-USE OF AGRICULTURAL AND NATIVE PLANTS IN A WESTERN AUSTRALIAN WHEAT-BELT CATCHMENT

Evaporation from annual crops at two densities, annual pasture, and perennial shrubland and heathland growing in similar landscapes of the wheat belt of Western Australia was estimated using the ventilated chamber method. For the agricultural plants, evaporation from the crops was higher than that of the annual pasture. Lupins consumed more water than wheat, but water use of the crops was not increased by doubling plant density. Perennial native shrubs and heaths evaporated more water than agricultural plants by withdrawing soil water throughout the year and by increasing evaporation rates following above average rainfall in summer and autumn. Possible strategies for using heath and shrubs to control salinity are discussed.